Which action is not an example of work? picking up a box off the floor

pushing a box across the floor

holding a tray in the cafeteria line

raising a barbell over your head

Which are examples of projectile motion? choose all that apply a. a soccer ball rolling across the ground in the northeast direction b. a car turning a corner, so it is heading south c. a javelin flying through the air d. a tennis ball lobbed over the net

6–43 a food department is kept at 2128c by a refrigerator in an environment at 308c. the total heat gain to the food department is estimated to be 3300 kj/h and the heat rejection in the condenser is 4800 kj/h. determine the power input to the compressor, in kw and the cop of the refrigerator.

The space between two 15-in.-long concentric cylinders is filled with glycerin (viscosity = 8.5 × 10-3 lb·s/ft2). the inner cylinder has a radius of 1 in. and the gap width between cylinders is 0.1 in. determine (a) the torque and (b) the power required to rotate the inner cylinder at 180 rev/min. the outer cylinder is fixed. assume the velocity distribution in the gap to be linear.